1. Field of the Invention
The present invention relates to a device which allows textured ceiling plaster or other free-flowing material or slurries such as "mud" to be applied on the sheetrock or other surfaces beyond the normal reach of the person applying it. A piston inside of a tube is connected to a puller wire that extends out one end of the tube, down a selected length of the tube, and terminates in a ratchet assembly at an intermediate section of the tube. The outer length of the wire is protected in a sheathing, and the wire is wound over a pulley by the ratchet assembly, drawing the piston toward the one end of the tube thereby expelling any material that may have been introduced into the tube. The material or plaster or slurry is introduced at the one end of the tube through a filler valve assembly, forcing the piston toward the remote end of the tube. The pulley is turned by depressing a ratchet handle that operates the ratcheting assembly. A pawl locks against each cog to prevent it from being oppositely rotated.
2. Description of the Prior Art
The prior art discloses various devices for use by one person to apply drywall texture and other materials. For example, U.S. Pat. No. 3,070,827 to Ames discloses a mastic applying tool in which a cylinder is moved with respect to a stationary piston using a cable. After the cylinder has been filled with mastic through a loading valve at the head of the cylinder the operator turns a drum, winding the cable thereon and drawing the cylinder toward an end cover at the head to which the cable is attached. In applicant's device, however, the cable is attached to and draws the piston toward the head of the cylinder which means that instead of moving a bulky cylinder he moves a relatively light piston. In effect, in Ames the piston is pushed through the cylinder whereas in applicant's device the piston is pulled through the mastic. The Ames device thus is submitted as not anticipating applicant's invention for these among other reasons.
U.S. Pat. No. 4,979,649 to Westcott concerns an extender apparatus for a caulking gun having an axially displaceable piston, a front face having an opening, and a trigger mechanism for incrementally advancing the piston along a predetermined axis, the extender including an elongated skeletal frame for supporting a cartridge of caulking compound. The device includes an adapter for connecting the frame to the front face of the caulking gun, an adjustable pivot for adjusting the relationship of the frame to the front face of the gun, and an auxiliary piston whereby a flexible shaft may be advanced incrementally by the incremental movement of the gun piston. The use of a cartridge and the absence of a piston in a cylinder alone patentably distinguish applicant's device over that of Wescott.
U.S. Pat. No. 4,948,054 to Mills discloses a portable sprayer powered by an air supply for applying a liquid texture material, and otherwise lacks many of the features of applicant's invention and therefore cannot anticipate applicant's invention. U.S. Pat. No. 4,784,598 to Kranz et al concerns a hand held resilient flexible application member and is not related to the piston delivery system of the present invention. U.S. Pat. No. 4,907,955 to Snipes is a drywall finishing tool that may be used to apply a layer of plastic but lacks the feature to feed plaster, mud, etc. as in the present invention. U.S. Pat. No. 5,069,610 to Milburn concerns another form of mastic or plastic material applicator and lacks any features that could be considered anticipatory of applicant's invention. U.S. Pat. No. 4,440,410 to Bradshaw relates to a hopper for containing drywall joint compound or "mud" used in covering seams between drywall panels and fails to anticipate any significant details of applicant's invention.
It can be readily appreciated that these references, either singly or in combination, do not teach suggest nor infer the method and means of the present invention for providing a piston assembly wherein a piston is pulled through a dispensing tube to apply plaster, "mud" or other slurries to sheetrock or other surfaces beyond the normal reach of persons applying it.